The data in the table and chart above was extracted from the world bank public data.

Correlation was calculated using "Pearson's correlation", Quote from Wikipedia:Pearson product-moment correlation coefficient is a measure of the correlation (linear dependence) between two variables X and Y, giving a value between +1 and -1 inclusive. It is widely used in the sciences as a measure of the strength of linear dependence between two variables. The correlation coefficient ranges from -1 to 1. A value of 1 implies that a linear equation describes the relationship between X and Y perfectly, with all data points lying on a line for which Y increases as X increases. A value of -1 implies that all data points lie on a line for which Y decreases as X increases. A value of 0 implies that there is no linear correlation between the variables.

The table below is an Interpretation of the degree of correlation between two variables:

Correlation | Negative | Positive |
---|---|---|

None | -0.09 to 0.0 | 0.0 to 0.09 |

Small | -0.3 to -0.1 | 0.1 to 0.3 |

Medium | -0.5 to -0.3 | 0.3 to 0.5 |

Strong | -1.0 to -0.5 | 0.5 to 1.0 |

The calculated value of the correlation coefficient between the GDP per capita, PPP (constant 2005 international $)Â and Fertility rate, total (births per woman) is -0.53, which means that there a strong negative correlation between GDP per capita in a country and the fertility rate of women and the fertilityÂ rate is likely to decrease as the GDP per Capita (or in other words the individual income) increases.